This is an open-label, phase 1b, proof-of-concept study to assess the safety and efficacy of EBP921, a prenylation inhibitor, in subjects chronically infected with delta hepatitis. Subjects will be randomized to receive one of two different doses of EBP921. Dosing will occur over 28-days and during that time, evidence of antiviral response will be assessed by frequent measurements of HDV-RNA via PCR assay. In addition, safety lab data will also be collected along with surveillance monitoring of HBV activity.